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[2a01:cb08:8949:7e00:2e3f:eaf8:ac5b:1b0d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488d5d768afsm183992125e9.2.2026.04.14.07.48.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2026 07:48:13 -0700 (PDT) Date: Tue, 14 Apr 2026 16:48:12 +0200 From: Paul Chaignon To: Puranjay Mohan Cc: bpf@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Xu Kuohai , Catalin Marinas , Will Deacon , Luke Nelson , Xi Wang , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Pu Lehui , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next v2 2/2] bpf, riscv: Remove redundant bpf_flush_icache() after pack allocator finalize Message-ID: References: <20260413191111.3426023-1-puranjay@kernel.org> <20260413191111.3426023-3-puranjay@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260413191111.3426023-3-puranjay@kernel.org> On Mon, Apr 13, 2026 at 12:11:09PM -0700, Puranjay Mohan wrote: > bpf_flush_icache() calls flush_icache_range() to clean the data cache > and invalidate the instruction cache for the JITed code region. However, > since commit 48a8f78c50bd ("bpf, riscv: use prog pack allocator in the > BPF JIT"), this flush is redundant. > > bpf_jit_binary_pack_finalize() copies the JITed instructions to the ROX > region via bpf_arch_text_copy() -> patch_text_nosync(), and > patch_text_nosync() already calls flush_icache_range() on the written > range. The subsequent bpf_flush_icache() repeats the same cache > maintenance on an overlapping range. > > Remove the redundant bpf_flush_icache() call and its now-unused > definition. > > Fixes: 48a8f78c50bd ("bpf, riscv: use prog pack allocator in the BPF JIT") > Acked-by: Song Liu > Signed-off-by: Puranjay Mohan Tested-by: Paul Chaignon [...]